power operated gates

[Stewart]

My daughter has a house in the countryside and the previous owner surrounded the land with high fencing including a gate. We wish to either convert the gate to power operation or instal a new gate. The problem is that there is no mains electric supply near the gate area. Does anyone know of a battery operated system (probably 12 volt) or other form of energy that would work such a gate. A new gate could be a roller gate or single pivot. We would fit switches on both sides of the gate to allow operation. Thank you

[Jim]

Perhaps this would be of interest:

[Harry Bloomfield]

Pneumatics. You can buy air rams cheap enough and devices which act just like a switch, I would also think that these days you could even buy remote control battery operated air switches. Just add a means to compress air and store it.

[andrew]

Use the weight of the car driving over a series of tubes to recharge the reservoir?

AJH

[Dave Liquorice]

I don't think you'd get enough pressure or volume from a simple tyre over tube system that but a plate that used mechanical advantage and compressed a 6' length of tube might. Or a plate with a load of cylinders underneath?

Interesting idea.

[Jim]

Perhaps you could collect rainwater and use it to power some kind of water machine?

[Owain]

Owain

[Jules]

Wind turbine. If there's not enough wind when you need to drive through, get out of the vehicle and blow on the blades.

[Stewart]

Thank you all; it looks like the best way is to instal a new gate and operate it with a 12 volt motor charged by a solar panel. We shall contact the electric gate shop as suggested and get their info.

[Andy Dingley]

Plenty of them. Nearly as many that have solar charging. Search the commercial suppliers then think about doing it yourself, but do the sizing calculations carefully. Personally I don't mind opening the gate myself when it's warm and dry, but not when it's cold, dark and raining. Winter capacity could be a problem.

Another system (tried it myself) is low-pressure water hydraulics, i.e. a water balance system driven by weight, rather than one with direct-acting pressure rams. Many locations have no electricity but do have a stream. Mine had to use a hydraulic ram to lift the water to the gate, as there was a large stream with huge capacity, but it was below the gate level.

[andrew]

I wonder, our electric gate takes 20 seconds to open and close, weighs 3 tonne and has a 1kW induction motor. In fact for a lot of heavy duty uses a

12V motor, as on a winch, is more effective and not limited by power cycles. Say we average half power, that's 500W for 40 seconds, 20000 Joules. A 1 tonne vehicle falling through 2m. How efficient are pneumatic systems? Adiabatic compression to isothermal store will cost you half I suppose.

So you'd need a sinuous tube with a few one way valves in each loop, such that the tyre misses the valves. Then as long as the tyre only just flattens the tube and the total movement is 4m... Lots of tube though.

In practice they'd need to be a number of these series peristaltic type pumps in parallel to give both pressure and volume. Solar power might just supply the solenoid control.

Actually I'm quite impressed by my solar PIR parking light.

AJH

[John]

Plenty of them. Nearly as many that have solar charging. Search the commercial suppliers then think about doing it yourself, but do the sizing calculations carefully. Personally I don't mind opening the gate myself when it's warm and dry, but not when it's cold, dark and raining. Winter capacity could be a problem.

Another system (tried it myself) is low-pressure water hydraulics, i.e. a water balance system driven by weight, rather than one with direct-acting pressure rams. Many locations have no electricity but do have a stream. Mine had to use a hydraulic ram to lift the water to the gate, as there was a large stream with huge capacity, but it was below the gate level.

I regularly go through on- and keep meaning to take my oil can - I am sure a drop of oil would make it faster to open.

[Bruce]

Then buy a spare 12V battery. Keep one on trickle charge and swap them as often as needed to ensure that the gate always works.